Population dynamics and breeding patterns of Mastomys natalensis Smith 1932 in irrigated rice in eastern Tanzania

Mulungu, L.S., Ngowo, V., Mdangi, M., Katakweba, A.S., Tesha, P., Mrosso, F.P., Mchomvu, M

Domestic Cat (Felis silvestris catus) Urine Odour as a Potential Rodent Management Strategy

The aim of this study was to investigate the effects of cat urine odour extract on rodent pest species to reduce crop losses. Cat urine from the captured cats was drawn using cat catcher. Urinary catheter was inserted into the urethra up to the urinary bladder and a syringe attached to the urinary catheter was used to draw urine which was stored in universal bottles at a temperature below -20ºC. The stored cat urine was directly bound to the maize starch by slowly mixing the urine with the starch until dough was formed which was then granulated. The granules were dried at room temperature and packed in a tight closed jar. Mastomys natalensis of 25 – 40 g were used in this study. Wild captured individuals were acclimatized in a room for 7 days prior to experiment by providing them with food and water. The effect of cat urine odours on rodent pest species was studied in a single box. Camera traps were set at the top of each room in order to monitor rodents’ activities. Our Findings suggests that cat urine odour has a potential to repel rodent pest species whereas female cat urine was more effective than male cat urine. However, more investigations are needed to evaluate its effectiveness under field conditions

Survival and recruitment of the multimammate mouse, Mastomys natalensis (Smith 1834), in a rice agro-ecosystem

We investigated the recruitment and survival of the multimammate mouse, Mastomys natalensis, within irrigated rice and fallow field habitats at different time periods related to rice crop growth stages. Capture-Mark-Recapture data were collected for M. natalensis each month from June 2010 to May 2012, and both recruitment and survival were estimated in relation to land use (irrigated rice or fallow field) within the agro-ecosystem. Higher recruitment and survival were observed in rice fields than in fallow fields suggesting the relationship was compensatory when there was a higher abundance of food resources. In terms of management, farmers in the study area should implement management strategies in rice fields at both transplanting and maturity stages of crop growth in order to maintain recruitment and survival at low levels.The Zonal Agricultural Research and Development Funds (ZARDEF) through Eastern Zone.http://www.degruyter.com/view/j/mamm2017-03-30am2016Mammal Research InstituteZoology and Entomolog

Aquatic habitats of the malaria vector Anopheles funestus in rural south-eastern Tanzania

Background: In rural south-eastern Tanzania, Anopheles funestus is a major malaria vector, and has been implicated in nearly 90% of all infective bites. Unfortunately, little is known about the natural ecological requirements and survival strategies of this mosquito species. Methods: Potential mosquito aquatic habitats were systematically searched along 1000 m transects from the centres of six villages in south-eastern Tanzania. All water bodies were geo-referenced, characterized and examined for presence of Anopheles larvae using standard 350 mLs dippers or 10 L buckets. Larvae were collected for rearing, and the emergent adults identified to confirm habitats containing An. funestus. Results: One hundred and eleven habitats were identified and assessed from the first five villages (all < 300 m altitude). Of these, 36 (32.4%) had An. funestus co-occurring with other mosquito species. Another 47 (42.3%) had other Anopheles species and/or culicines, but not An. funestus, and 28 (25.2%) had no mosquitoes. There were three main habitat types occupied by An. funestus, namely: (a) small spring-fed pools with well-defined perimeters (36.1%), (b) medium-sized natural ponds retaining water most of the year (16.7%), and (c) slow-moving waters along river tributaries (47.2%). The habitats generally had clear waters with emergent surface vegetation, depths > 0.5 m and distances < 100 m from human dwellings. They were permanent or semi-permanent, retaining water most of the year. Water temperatures ranged from 25.2 to 28.8 °C, pH from 6.5 to 6.7, turbidity from 26.6 to 54.8 NTU and total dissolved solids from 60.5 to 80.3 mg/L. In the sixth village (altitude > 400 m), very high densities of An. funestus were found along rivers with slow-moving clear waters and emergent vegetation. Conclusion: This study has documented the diversity and key characteristics of aquatic habitats of An. funestus across villages in south-eastern Tanzania, and will form an important basis for further studies to improve malaria control. The observations suggest that An. funestus habitats in the area can indeed be described as fixed, few and findable based on their unique characteristics. Future studies should investigate the potential of targeting these habitats with larviciding or larval source management to complement malaria control efforts in areas dominated by this vector species

Effect of synthetic hormones on reproduction in Mastomys natalensis

Rodent pest management traditionally relies on some form of lethal control. Developing effective fertility control for pest rodent species could be a major breakthrough particularly in the context of managing rodent population outbreaks. This laboratory-based study is the first to report on the effects of using fertility compounds on an outbreaking rodent pest species found throughout sub-Saharan Africa. Mastomys natalensis were fed bait containing the synthetic steroid hormones quinestrol and levonorgestrel, both singly and in combination, at three concentrations (10, 50, 100 ppm) for seven days. Consumption of the bait and animal body mass was mostly the same between treatments when analysed by sex, day and treatment. However, a repeated measures ANOVA indicated that quinestrol and quinestrol+levonorgestrel treatments reduced consumption by up to 45%, particularly at the higher concentrations of 50 and 100 ppm. Although there was no clear concentration effect on animal body mass, quinestrol and quinestrol+levonorgestrel lowered body mass by up to 20% compared to the untreated and levonorgestrel treatments. Quinestrol and quinestrol+levonorgestrel reduced the weight of male rat testes, epididymis and seminal vesicles by 60-80%, and sperm concentration and motility were reduced by more than 95%. No weight changes were observed to uterine and ovarian tissue; however, high uterine oedema was observed among all female rats consuming treated bait at 8 days and 40 days from trial start. Trials with mate pairing showed there were significant differences in the pregnancy rate with all treatments when compared to the untreated control group of rodents

Winning the fight against rodent pests: Recent developments in Tanzania

Rodent management programs in Tanzania have been reactive and did not consider the population ecology of the target species. The strategies used to manage rodents were probably most suited to managing low-density rodent populations and were selected to solve localised rodent problems in certain areas. These included bounty schemes, burning of homes and vegetation, trapping and poisoning. In recent years, new developments in rodent pest management include a system designed to provide early warning of potent damage. An understanding of the population processes that give rise to rodent pest's problems provides the framework for evaluating the causes and solutions. Population models for predicting outbreaks have been developed. These have incorporated simulations and aspects of economics in the implementation of control strategies. Simulation based on Bioeconomics models have shown that the most economically rewarding strategies differ significantly from current practices of symptomatic treatment when severe rodent damage is noticed in the fields. Therefore, shifting from symptomatic practices and controlling rodents on a calendar basis can substantially improve the economic conditions for the majority of maize products in Tanzania

Soil type limits population abundance of rodents in crop fields: case study of the multimammate rat Mastomys natalensis Smith, 1834 in Tanzania

Integrative Zoology 2008; 3:27-30Studies of populations of the multimammate rat Mastomys natalensis in Morogoro, Tanzania, show that soil texture appears to influence the population abundance and distribution of these rats in agricultural fields. The lowest rodent population abundance was found on sandy clay soils (F (2, 5) = 8.42; P = 0.025). The population abundances of M. natalensis on sandy clay loam and sandy loam soils did not differ significantly (P ≤ 0.05), possibly because these soils have a very similar texture. The results of this study suggest that M. natalensis prefers loam-textured soils with a high percentage of sand, which are probably better than clay soils for burrowing and nesting, particularly in the rainy season. The lower preference for clay soils is probably related to the poor aeration in these soils and the waterlogging that occurs during the wet season.SUA - VLIR Programm

Soil type limits population abundance of rodents in crop fields: case study of the multimammate rat Mastomys natalensis Smith, 1834 in Tanzania

Integrative Zoology 2008; 3:27-30Studies of populations of the multimammate rat Mastomys natalensis in Morogoro, Tanzania, show that soil texture appears to influence the population abundance and distribution of these rats in agricultural fields. The lowest rodent population abundance was found on sandy clay soils (F (2, 5) = 8.42; P = 0.025). The population abundances of M. natalensis on sandy clay loam and sandy loam soils did not differ significantly (P ≤ 0.05), possibly because these soils have a very similar texture. The results of this study suggest that M. natalensis prefers loam-textured soils with a high percentage of sand, which are probably better than clay soils for burrowing and nesting, particularly in the rainy season. The lower preference for clay soils is probably related to the poor aeration in these soils and the waterlogging that occurs during the wet season.SUA - VLIR Programm

Comparative study of movement patterns of Mastomys natalensis in irrigated rice and fallow fields in eastern Tanzania

African Journal of Ecology 2015; 53:473-479A 2-year capture–mark–recapture study was conducted to estimate home ranges and weekly travel distance of Mastomys natalensis (Smith 1834) in an irrigated rice ecosystem and fallow fields. We found that adults have larger home ranges than subadults in fallow fields but not in rice fields, indicating that fallow fields are more suitable for breeding. Travel distances were larger in rice fields, especially in the transplanting stage, during which rice fields are flooded and provide less food, causing movements into neighbouring fallow fields that then temporarily experience higher population density. A decrease in travel distance was observed in rice fields during the maturity stage, which can be explained by higher food availability and a more suitable, nonflooded situation. Movement of M. natalensis in rice-fallow mosaic landscapes thus seems to be driven by food availability and flooding status of the rice fields, which can be attributed to land use practices